Isaiah 14:3 (King James Bible) the LORD shall give thee rest from thy sorrow and from thy fear and from the hard bondage wherein thou wast made to serve
As Oliver Cowdery was copying from 𝓞 into 𝓟, he initially wrote the plural sorrows, but then he immediately corrected his error by erasing the plural s, thus giving sorrow (the King James reading). He was probably expecting a plural noun after the phrase “rest from”, as in Revelation 14:13 (“that they may rest from their labors”) and in these two examples elsewhere in the Book of Mormon text:
Note in the last example that the text once more has the singular sorrow (as well as care) but in this case after a preceding plural, troubles.
Summary: Maintain the singular sorrow in 2 Nephi 24:3, the King James reading.